mastery (n.)

c. 1200, mesterie, maistrie, "state or condition of being a master, control, dominance," also "superiority, ascendancy, the upper hand, victory in war or a contest;" from Old French maistrie (Modern French maîtrise), from maistre "master" (see master (n.)). Meaning "intellectual command" (of a topic, art, etc.), "expert skill" is from c. 1300.